Antibacterial compositions

1. A compound of formula (I), or a salt or N-oxide thereof:

wherein:

m is 0 or 1;

Q is hydrogen or cyclopropyl;

Alk is an optionally substituted, divalent C 1 -C 6 alkylene, alkenylene or alkynylene radical which may contain an ether (—O—), thioether (—S—) or amino (—NR)— link, wherein R is hydrogen, —CN or C 1 -C 3 alkyl;

X is —C(═O)NR 6 —, —S(O)NR 6 —, —C(═O)O— or —S(═O)O— wherein R 6 is hydrogen, optionally substituted C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, -Cyc, or —(C 1 -C 3 alkyl)-Cyc wherein Cyc is optionally substituted monocyclic carbocyclic or heterocyclic having 3-7 ring atoms;

Z is N or CH, or CF;

R 2 is a group Q 1 -[Alk 1 ] q -Q 2 -, wherein

q is 0 or 1;

Alk 1 is an optionally substituted, divalent, straight chain or branched C 1 -C 6 alkylene, or C 2 -C 6 alkenylene or C 2 -C 6 alkynylene radical which may contain or terminate in an ether (—O—), thioether (—S—) or amino (—NR)— link;

Q 2 is an optionally substituted divalent monocyclic carbocyclic or heterocyclic radical having 5 or 6 ring atoms or an optionally substituted divalent bicyclic carbocyclic or heterocyclic radical having 9 or 10 ring atoms;

Q 1 is hydrogen, an optional substituent, or an optionally substituted carbocyclic or heterocyclic radical having 3-7 ring atoms;

R 3 is a group Q 4 -[Alk 2 ] p -[Q 3 ] q - wherein

p is 0 or 1;

q is 1;

Alk 2 is optionally substituted divalent C 1 -C 6 alkylene or C 2 -C 6 alkenylene or C 2 -C 6 alkynylene radical;

Q 3 is an optionally substituted divalent monocyclic carbocyclic or heterocyclic radical having 5 or 6 ring atoms or an optionally substituted divalent bicyclic carbocyclic or heterocyclic radical having 9 or 10 ring atoms;

Q 4 is hydrogen, an optional substituent, or optionally substituted carbocyclic or heterocyclic ring having 3-7 ring atoms.

2. A compound as claimed in claim 1 wherein Z is CH.

3. A compound as claimed in claim 1 wherein m is 1 and Q is hydrogen, Alk is —CH 2 CH 2 —, and X is —C(O)NH—.

4. A compound as claimed in claim 1 wherein Q 2 is an optionally substituted pyridine, pyrimidine, or pyrazine ring.

5. A compound as claimed in claim 1 wherein Alk 1 is present and is an optionally substituted divalent C l -C 3 alkylene radical, which optionally includes an —NH— link, or optionally terminates in an —NH— link to Q 2 .

6. A compound as claimed in claim 1 wherein Q 4 is hydrogen and p is 0.

7. A compound as claimed in claim 1 wherein Q 3 is an optionally substituted pyridine ring, an optionally substituted pyrimidine ring or an optionally substituted pyrazine ring.

8. A compound as claimed in claim 1 wherein Q 2 is an optionally substituted pyridine-2-one ring.

9. A pharmaceutical composition comprising a compound as claimed in claim 1 , together with a pharmaceutically acceptable carrier.